The present disclosure relates to an optical scanning device including a configuration for passing a light beam emitted from a light source through scanning lenses to image the light beam onto a surface to be scanned, and an image forming apparatus including the optical scanning device.
A general optical scanning device used in an image forming apparatus such as a laser printer includes a light source configured to emit a laser beam, a deflector configured to deflect the laser beam to scan it over a surface to be scanned, and scanning lenses configured to image the deflected laser beam onto a circumferential surface (surface to be scanned) of a photoconductive drum. In the case of a color-type image forming apparatus, a plurality of light sources and photoconductive drums are respectively provided for each color. On the other hand, in some tandem-type color image forming apparatuses, an imaging optical system including the deflector and the scanning lenses is shared by a plurality of laser beams.
It is necessary to minimize a dimensional error of a mold for molding the scanning lens in order to allow the scanning lens to obtain predetermined optical properties. In particular, a scanning lens through which a plurality of laser beams pass (hereinafter, also referred to as “common scanning lens”) has a high error sensitivity and, therefore, requires further reduction in the dimensional error of the mold.